The present invention relates to a decompression device in internal combustion engines of the kind comprising a decompression cam or like element mounted on a controllable operating spindle for actuating a valve which is to be influenced by the decompression device. The decompression cam keeps an element, for example, a cam follower, which transmits the operative lift of the camshaft cam to the valve, in a decompression position wherein it is spaced away from the position which is determined by the base circle of the cam on the camshaft of the engine. A ratchet wheel is connected to the operating spindle, which extends along the length of and parallel to the engine camshaft and is adapted to co-act with a trip element for restoring the decompression cam to its original position.